how to run a button when i click enter ?

I'm assuming you want to "click" a button when the user presses enter on a textbox, for example, and that you're working with winforms.

You need to handle the KeyDown or KeyUp event of the textbox and depending on the key pressed call the PerformClick() event of the button.

Do your want to work on Button_Click() event on clicking the button or something else? Please explain.

Please note that Button Control also works with enter key (if focused when enter key pressed). You can use tab to move your focus to that button. And Tabindex property of form controls is useful to set tab index for your control.

You can set AcceptButton[^] property to the button in your Form what handles the data entered.

And remember, just setting the AcceptButton/CancelButton is not enough. This just tell which button should be invoked on ENTER/ESC. We have to set the DialogResult in the Button handler.

button1.DialogResult = System.Windows.Forms.DialogResult.OK;
button2.DialogResult = System.Windows.Forms.DialogResult.Cancel;

form1.AcceptButton = button1;
form1.CancelButton = button2;

And... (Kim Togo...Don't Repeat Yourself) - Look at this answer[^]: